Evolved gas analysis of hydrated phases in Murchison and Orgueil

To better characterise the hydrated minerals in chondrites Evolved Gas Analysis of Murchison, Orgueil and selected minerals has been carried out. Meteorite water release profiles show significant differences to expected reference minerals

Mining revival

In relation to its size the United Kingdom (UK) is remarkably well-endowed with mineral resources as a result of its complex geological history. Their extraction and use have played an important role in the development of the UK economy over many years and minerals are currently worked at some 2100 mine and quarry sites. Production is now largely confined to construction minerals, primarily aggregates, energy minerals and industrial minerals including salt, potash, kaolin and fluorspar, although renewed interest in metals is an important development in recent years

Raman spectroscopy of the copper chloride minerals nantokite, eriochalcite and claringbullite - implications for copper corrosion

The application of Raman spectroscopy to the study of the copper chloride minerals nantokite, eriochalcite and claringbullite has enabled the vibrational modes for the CuCl, CuOH and CuOH2 to be determined. Nantokite is characterised by bands at 205 and 155 cm-1 attributed to the transverse and longitudinal optic vibrations. Nantokite also has an intense band at 463 cm-1, eriochalcite at 405 and 390 cm-1 and claringbullite at 511 cm-1. These bands are attributed to CuO stretching modes. Water librational bands at around 672 cm-1 for eriochalcite have been identified and hydroxyl deformation modes of claringbullite at 970, 906 and 815 cm-1 are observed. Spectra of the three minerals are so characteristically different that the minerals are readily identified by Raman spectroscopy. The minerals are often determined in copper corrosion products by X-ray diffraction. Raman spectroscopy offers a rapid, in-situ technique for the identification of these corrosion products

Formation of magnetic minerals at hydrocarbon-generation conditions

In this paper, we report the pyrolysis and formation of magnetic minerals in three source rock samples from the Wessex Basin in Dorset, southern England. The experimental conditions in the laboratory recreated the catagenesis environment of oil source rocks. Magnetic analysis of both the heated and the unheated samples at room temperature and at very low-temperatures (5 K), coupled with transmission electron-microscopy imaging and X-ray analysis, revealed the formation of nanometre-sized (<10 nm), magnetic particles that varied across the rock samples analysed, but more importantly across the pyrolysis temperature range. Magnetic measurements demonstrated the formation of these magnetic minerals peaked at 250 °C for all rock samples and then decreased at 300 °C before rising again at 320 °C. The newly formed magnetic minerals are suggested to be primarily pyrrhotite, though magnetite and greigite are also thought to be present. The sizes of the magnetic minerals formed suggest a propensity to migrate together with oil potentially explaining the magnetic anomalies observed above and within oil fields

Structural Modification of KAISiO4 Minerals

Kalsilite, a polymorph of KAISiO4 is an end member of nepheline-kalsilite series and the mineral was syn-thesized by hydorhermal methods. The synthetic kalsilite is hexagonal, P63, with a=5.151(5), c=8.690(8) A. The structure was refined by full-matrix least-squares methods to a R-value 0.084, using 373 observed reflections. The obtained structure agrees well with those of the natural and the alkali-exchanged specimens reported in the previous literatures. The oxygen atoms are disordered at two mirror-equivalent sites, constructing the domain structure. The average domain structure shows P63mc symmetry and the strctural relation between the two P63 structure corresponds to the twinning by merohedry. The domain structure was considered to be caused accompanied with the high-low inversion of the kalslite structure. Heating experiments of kalsilite reveal that the X-ray powder pattern changes at 865℃, and that cell dimensions vary discontinuously at this temperature. It was confirmed that kalsilite underwent a displacive transition like those observed in quartz or tridymite. The high-form is refered as 'high-kalsilite', and a possible simulate model is proposed. The structure of the high-kalsilite at 950℃ was refined byfull-matrix least-squares methods to a R-value 0.095, using 115 observed reflections. The high-kalsilite is also hexagonal, P63mc or P63/mmc, with a=5.288(1), c=8.628(5) A at 950℃. The structure almost prefectly coincides with that of the simulated model. Based on the interatomic distances, the distribution of silicon and aluminum atoms is found to be or-dered and the space group is determined to be P63mc. Kaliophilite and the related orthorhombic from, polymorphs of KAISiO4, were synthesized by dry method. The synthetic kaliophilite (kaliophilite-H2) is hexagonal with a=5.17(1), c=8.49(3) A, and the orthorhombic KAISiO4 (kaliophilite-O1) is orthormbic with a=9.01(1), b=15.60(2), c=8.53(4) A. Detailed examina-tion of the obtained powder patterns together with that of simulated model indicates that the kaliophilite-H2 has a disorderd structure of four types of the low-kalsilite. The structure was refined by the X-ray powder pattern-fitting method (Rietvelt method) to a R-value 0.121

Trial calculation of relating the equilibrium state of minerals to the descriptive mineralogy

Statistical calculation have been carried out on the volumes of the asymmetric unit of minerals. This treatment is related to the origin of the symmetry and periodicity of the crystals, and to the equilibrium conditions of these crystals. From the view point of the cohesion energy, if the crystals were grown under the condition of nearly perfect equilibrium states, than all the volumes of the asymmetric unit of each crystal structure will be approximately equal, and if the volume of the asymmetric units of a certain mineral is larger than the average value, this mineral is considered to be grown in a metastable condition. The calculation of the cell dimensions of minerals have been carried out by the use of deta from previous investigations. The statistical consideration of the volumes of the asymmetric unit of minerals is considered to be an appropriate criterion to relate the stability of minerals to their descriptive mineralogy